Molecularly Imprinted Electroimpedance Sensor for Detection of 8-Isoprostane in Exhaled Breath Condensate

Soft lithographically patterned molecularly imprinted polymers (MIP) offer highly durable, low-cost fabricated biochemical sensors, with a highly selective biorecognition mechanism. In MIP architecture, nanocavity binding sites are imprinted onto a polymer thin film coated over an interdigitated electrode structure. As the target molecules affixed to the binding sites, the frequency-dependent electroimpedance is measured across the interdigitated electrode, and the response signal is analyzed to determine analyte concentration. This letter uses poly(vinyl alcohol), N-methyl-4 (4'-formylstyryl)pyridinium methosulfate acetal (PVA-SbQ) to create the desired MIP thin film structure for detecting specific physiologically relevant small molecules, 8-isoprostane, and an oxidative stress biomarker clinical tested in blood or saliva samples. The sensor devices were rigorously tested against comparable biomolecules, including cortisol, cortisone, and progesterone, demonstrating very minimal cross sensitivity, mostly at very high concentrations and well above their physiological concentration range in exhaled breath condensate. The detectable range of 8-isoprostane in aerosolized test and control samples mimicking exhaled breath condensate was identified as 1-100 pg/mL, which comfortably covers the reported physiological concentration range (10-100 pg/mL) of this biomarker in exhaled breath.